An administrator notices that several servers have become noticeably slower. Logs show that an optional update was applied to these same servers. A BEST practice before running updates is:

A performance baseline captures key system metrics such as CPU utilization, memory usage, disk I/O, and network throughput before any changes are made. If an optional update causes slowness, the baseline provides concrete data to confirm the degradation and isolate the update as the cause. This is a recognized best practice in change management that enables measurable, objective comparisons to support troubleshooting and rollback decisions.

Updating BIOS firmware is an unrelated maintenance task that does not help evaluate the impact of an OS or application-level update on server performance.

Taking a complete backup is also a best practice before updates for recovery purposes, but it does not provide the performance reference data needed to detect or diagnose a performance regression caused by the update.

Restarting servers before applying updates clears temporary state but does not establish any measurable performance reference and cannot help identify whether a subsequent update has degraded performance.